The Australian Immunisation Handbook 10th Edition 2013

• Gardasil – CSL Limited/Merck & Co Inc (recombinant protein
particulate [VLP] vaccine containing the major capsid [L1] protein
of HPV types 6, 11, 16 and 18; 4vHPV). Each 0.5 mL monodose
vial or pre-filled syringe contains 20 µg HPV-6 L1 protein, 40 µg
HPV-11 L1 protein, 40 µg HPV-16 L1 protein and 20 µg HPV-18
L1 protein, adsorbed onto 0.225 mg of aluminium as aluminium
hydroxyphosphate sulphate; 0.780 mg L-histidine; 50 µg polysorbate
80; 35 µg sodium borate. May also contain yeast proteins.
The 2vHPV and 4vHPV vaccines have been assessed in females in a number
of international clinical trials. When given as a 3-dose series, HPV vaccines
elicit a neutralising antibody level many times higher than the level observed
following natural infection. 61,62 Overall, seroconversion occurs in 97 to 100%
of those vaccinated. 63-65 In women who are naïve to HPV types 16 and 18 prior
to vaccination, both vaccines are highly effective at preventing type-specific
persistent infection and related cervical disease (approximately 90 to 100%). 66-71
The 4vHPV vaccine also has established efficacy (100%; 95% CI: 94–100%)
against external anogenital and vaginal lesions (genital warts, and vulval,
vaginal, perineal and perianal dysplasias) associated with HPV types 6, 11,
16 or 18 in women.
In women who are vaccinated irrespective of their baseline HPV status (i.e.
women who may have pre-existing HPV infection), vaccine efficacy is lower than
observed in HPV-naïve women, indicating reduced vaccine effectiveness among
women who are already sexually active. This is because both HPV vaccines are
prophylactic vaccines (i.e. preventing primary HPV infection). Vaccination will
not treat an existing HPV infection or prevent disease that may be caused by an
existing HPV vaccine-type infection. 63,72,73 However, vaccination may still provide
benefit for sexually active women by protecting them against new infections with
other vaccine-preventable HPV types.
The efficacy of 4vHPV in males aged 16–26 years has been demonstrated
in one clinical trial. 74 Vaccination was greater than 85% protective against
persistent anogenital infection and external genital lesions due to vaccine HPV
types among HPV-naïve participants. Among HPV-naïve MSM participants
within the clinical trial, vaccine efficacy was 95% against intra-anal HPV
infection and 75% against high-grade anal intraepithelial neoplasia from
vaccine HPV types. Efficacy of 2vHPV vaccine in males has not been assessed
to date; however, the vaccine has demonstrated safety and immunogenicity in
males aged 10–18 years. 75
There is some evidence of HPV vaccine providing some cross-protection to
disease due to other HPV types in women: 4vHPV vaccine against cervical
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4.6 HUMAN PAPILLOMAVIRUS